ATHENS, Greece – Archaeologists said Friday they have unearthed a lavish burial site at the seat of the ancient Macedonian kings in northern Greece, heightening a 2,300-year-old mystery of murder and political intrigue.

The find in the ruins of Aigai came a few meters (yards) from last year’s remarkable discovery of what could be the bones of Alexander the Great‘s murdered teenage son, according to one expert.

Archaeologists are puzzled because both sets of remains were buried under very unusual circumstances: Although cemeteries existed near the site, the bones were taken from an unknown first resting place and re-interred, against all ancient convention, in the heart of the city.

Excavator Chrysoula Saatsoglou-Paliadeli said in an interview that the bones found this week were inside one of two large silver vessels unearthed in the ancient city’s marketplace, close to the theater where Alexander’s father, King Philip II, was murdered in 336 B.C.

She said they arguably belonged to a Macedonian royal and were buried at the end of the 4th century B.C.

But it is too early to speculate on the dead person’s identity, pending tests to determine the bones’ sex and age, said Saatsoglou-Paliadeli, a professor of classical archaeology at the Aristotle University of Thessaloniki.

She said one of the silver vessels is “very, very similar” to another found decades ago at a nearby royal tumulus, where one grave has been identified as belonging to Philip II.

Alexander was one of the most successful generals of all times. In a series of battles against the Persian Empire, he conquered much of the known world, reaching as far as India.

After his death in 323 B.C., at the age of 32, Alexander’s empire broke up in a series of wars by his successors that saw the murder of his mother, half brother, wife and both sons.

Archaeologist Stella Drougou said the new find is “very important, as it follows up on last year’s.”

“It makes things very complex,” she said. “Even small details in the ancient texts can help us solve this riddle. We (now) have more information, but we lack a name.”

Drougou told The Associated Press that the fact the funerary urns were not placed in a proper grave “either indicates some form of punishment, or an illegal act.”

“Either way, it was an exceptional event, and we know the history of the Macedonian kings is full of acts of revenge and violent succession.”

Drougou, who was not involved in the discovery, is also a professor of classical archaeology at the Aristotle University.

Saatsoglou-Paliadeli believes the teenager’s bones found in 2008 may have belonged to Heracles, Alexander’s illegitimate son who was murdered during the wars of succession around 309 B.C. and buried in secret. The remains had been placed in a gold jar, with an elaborate golden wreath.

“This is just a hypothesis, based on archaeological data, as there is no inscription to prove it,” she said.

At a cemetery in nearby Vergina, Greek archaeologists discovered a wealth of gold and silver treasure in 1977. One opulent grave, which contained a large gold wreath of oak leaves, is generally accepted to have belonged to Philip II. The location of Alexander’s tomb is one of the great mysteries of archaeology.

The sprawling remains of a large building with banquet halls and ornate mosaics at Aigai — some 190 miles (300 kilometers) north of Athens — has been identified as Philip’s palace.

The city flourished in the 6th and 5th centuries B.C., attracting leading Greek artists such as the poet Euripides. The Macedonian capital was moved to Pella in the 4th century B.C., and Aigai was destroyed by the Romans in 168 B.C.